Get Constraint Force node always returns a magnitude zero vector

Get Constraint Force node always returns a magnitude zero vector.

Repro Rate: 3/3

Tested this in //UE4/Release-4.27 @ CL#18319896 and was able to get the constraint force, it is a regression.

1. Create a new blank BP project
2. Add a Cylinder into the scene
3. In Details, set the Cylinder to Simulate Physics
4. Duplicate the Cylinder and move it apart
5. Add a Physics Constraint actor into the scene in-between the two Cylinders
6. In Details, set the Constraint Actors to Cylinder 1 & Cylinder 2
7. Move the Cylinders & Physics Constraint so that one Cylinder will fall off the edge with another staying on-top of the platform.
8. With the Physics Constraint Selected, open the Level Blueprint
9. Right-Click and create a reference to the Physics Constraint
10. Drag out from the Physics Constraint and place a "Get Constraint Force" node
11. Add in the "Event Tick" node and hook up the execution to the "Get Constraint Force" node
12. From the "Get Constraint Force" node, print out the values of the Linear Force & Angular Force vectors
13. Play in Editor

Results: "Get Constraint Force" node always return zero length vectors.
Expected: "Get Constraint Force" node returns the value of the Constraint Force being applied